80x100 Steel Gymnasium Building

The estimate at 80x100 moves with four computed quantities: 8,000 square feet of floor, 360 feet of perimeter, 7,200 square feet of wall and 8,433 square feet of roof. Everything else is site and specification. Circulation width is the first thing surrendered under pressure and the first thing missed afterwards.

Proportion drives cost here as much as size does: 360 ft of wall around 8,000 sq ft is 0.045 ft of wall per enclosed square foot, and a squarer plan of the same area would carry less. Framed openings, interior finish and the height chosen for the 80 ft span move the figure further than the footprint alone does.

• clear height above the playing surface
• the clear span across the court and its run-off
• the support wing with changing rooms
• impact-resistant lighting and interior surfaces

This page is ordered around height and clearance, because at 80x100 the 20-foot eave limits a steel gymnasium sooner than the plan does.

The footprint holds 2 court envelopes — 2 across by 1 deep — and leaves 42 feet of depth for an officials and team edge at one side, so benches and scoring do not sit inside the clearance zone.

What distinguishes 80x100 is depth behaviour: 1 row along 100 feet after 14 feet of circulation, with 42 feet unaccounted for at the end of the run. Where the building sits on the site changes how much of this floor is genuinely reachable.

A 80 by 100 footprint is a mildly directional plan: 8,000 sq ft enclosed by 360 ft of wall, at a 1.3:1 length-to-width proportion. Along its 100 ft dimension it takes 2 runs of court envelopes at 44 ft, leaving 12 ft over — the 12 ft is where the argument about this size actually happens. A competition floor is a single dimensioned object with an empty margin around it, and the building is a container for both. The planning failure that recurs is sizing the shell to the marked area and discovering the margin has nowhere to go. Heating a tall clear volume is an operating decision made at the envelope stage.

This footprint is planned as a single competition floor planned around one marked area and its clearances. Use is event-shaped: nothing for hours, then a concentrated arrival, an occupied period and a concentrated departure. The building has to absorb two crowd movements and a floor that must be clear between them. Timetable changeover, not session length, is what the entry and circulation routes are sized for.

The stored configuration carries a 20-foot eave and computes to 33.3 feet at the ridge on a 4:12 pitch — a 13.3-foot rise across 80 feet. Height is therefore not uniform, and the sidewall is the constraint. Judge the plan by what has to happen on the worst day of the year, not on an average one.

Height on a 80 ft span is a separate decision from the 100 ft length, and it is the span that sets the frame's behavior. Raising the eave over 8,000 sq ft affects every bay along the 100 ft dimension, so it is a whole-building cost rather than a local one.

Ventilation across 8,000 square feet at this height: an intensively occupied volume with high activity levels, where air handling is planned for the occupied peak.

The activity pattern this floor could equally be planned around is an activity floor with a permanent spectator side: there is no concourse behind the seating, so spectators queue and stand at the floor edge. Dividing the 8,000 sq ft by the 34 by 44 ft court envelope gives roughly 2 positions before circulation is deducted a second time for cross movement. Whether the plan keeps 2 or drops to 1 is decided by whether the 32 ft across is spent on a wider aisle or a further part-width position.

Depth arithmetic leaves a working end zone here. 3,360 square feet sits past the last row, which is why 80x100 tends to be planned with an officials and team edge at one side, so benches and scoring do not sit inside the clearance zone designed in rather than added later. Snow, wind and site exposure change what this shape costs to build long before the interior plan does.

Spare width is the more valuable of the two leftovers here: a continuous 12-foot strip beats the same area stranded at the end of the run, because it touches every position along the way. Fire separation, egress and occupancy are determined for the specific building and can reshape this plan entirely.

Use is event-shaped: nothing for hours, then a concentrated arrival, an occupied period and a concentrated departure. The building has to absorb two crowd movements and a floor that must be clear between them. Timetable changeover, not session length, is what the entry and circulation routes are sized for. That movement pattern, not the 8,000-square-foot total, is what decides whether the leftover 42 feet is useful here.

The 80-foot gable can carry 2 openings, one per court envelope, with 12 feet of wall left for piers between and beside them — the arrangement that keeps each position independently reachable. Rows that cannot be entered independently end up used as one long space.

Entry is planned as a route past the floor rather than across it. An opening that delivers arrivals onto the marked area is the arrangement that has to be managed by staff at every event.

Nominal bay division computes to 4 bays at about 25 feet, narrower than the 34-foot module — so frame lines land inside positions and the interior has to be set out from the columns. The mezzanine that is added afterwards is the change order that reprices the frame.

A single row means nothing is trapped: every position faces the opening directly, which is this footprint's advantage over a deeper building of the same width. Storage expands until it meets a wall, so give it a wall on purpose.

A competition floor cannot be lengthened usefully; it is either the size it needs or it is a practice floor. Growth is therefore ancillary — changing, storage, spectator — rather than dimensional.

Configured as a single competition floor planned around one marked area and its clearances, 80x100 is judged on whether the 2 court envelopes it holds match the operation, and on whether the 12 feet of spare width leaves the route this mode depends on.

• Does the work need racking or work zones on both sides with a full vehicle lane down the middle, or does it need a second lane that this 80-foot span cannot give?
• Is the 100-foot length being bought for depth, or for the repeated bays — eight to ten repeated bays, which makes the layout a scheduling problem as much as a spatial one?
• What clear height does the activity need, measured to the lowest obstruction?
• Are the run-off margins protected from storage and seating?

• 40x80 holds the same 2 court envelopes but changes the leftover depth by -42 feet, which is where the difference is actually felt.
• 60x60 holds the same 2 court envelopes but changes the leftover depth by -28 feet, which is where the difference is actually felt.
• 50x80 holds the same 2 court envelopes but changes the leftover depth by -42 feet, which is where the difference is actually felt.

Because this footprint is planned as a single competition floor planned around one marked area and its clearances, the useful next reads are different from the ones a differently shaped steel gymnasium suggests: competition floor planning, court clearance planning, event circulation.